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Well been playing with my new Millermatic 130xp Pretty cool! I have about decided to weld sheet metel you have to use several small spot welds? Cant seem to run a continuous stitch with out burning thru.

Crap! I wasnt thru! my real question is I have some patch work to do on the hood created from rust. Some are small enough to fill in with weld some I will need to make a patch. What is trick to hold the patch in place while you weld it. My clamps arent long enough. Can you use a magnet? Thanks :p

Mallard,
When welding sheetmetal "stitch weld" doing a short section and skip 2 or 3 lengths do another etc. all the way around the piece. When you get back to the start, do the adjacent sections.
Do this 'til all the dashes are connected. This keeps excess heat from building up which can make your sheetmetal stand and wave...
Bruce Palmer
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As for holding the patch in place until you get it tacked, try some masking tape. As long as the patch is fairly small and light, the tape will hold it in position until you can get a few tack welds in place. I've tried the magnets on small patches and did not have good luck with them. It seems when welding close to the magnets, the electrical current is screwed up somehow.

Another thing you can try is to make a tool from a peice of copper or brass to place behind a hole you may need to fill. It will keep the weld from falling through but the weld wont stick to it !

If tape won't hold the patch, drill a couple small holes and use screws to hold the patch in place. Tack it in, remove the screws, and weld up the holes when you're finish welding.

If you're welding in a flush patch(no overlapping joints at the edges), I've heard you could tack weld a couple of flat washers to your patch, then lay it in the hole, then tack your patch to the body and grind the tacks holding the washer onto the patch to remove it. Then you can weld the patch the rest of the way in. Give it a try. Might work O.K. for your situation.

You can also buy inter-grip welding clamps available from most good welding supply stores, they grip both panels aligning edges and leave a perfect gap for butt-welding.
GMCPaul

Eastwood sells several type clamps for just that purpose.

like the last message said, if there is no overlapping, they have these clamps that hold a nice 1/16 inch gap between materials.

http://www.eastwoodco.com/cgi-bin/sgin0101.exe

an economical (but tough to get in place) alternate to this clamp is very small machine screws with fender washers on either side to make your own clamps


if there are overlaps, they have pin hole clamps that work well, you'll need to drill an 1/8" hole through both pieces, insert the pin clamp. These work awesome for holding larger panels in place. so you may need quite a few. of course you will have to weld the pin holes, but if done properly, this can add a lot of strength, almost like little spot welds. Some guys use this method to stitch in patch panels.

http://www.eastwoodco.com/cgi-bin/s....HTM&UID=2002012207355906&FNM=20

an economical alternative to these clamps are tiny screws to hold the panels together.

The other tip I have, is practice on some old junk fenders, something with similiar metal surface, don't have your project be your practice piece. do this to fine tune your welder setups. I do it everytime before welding on the vehicle, just to make sure! i keep some scrap metal around just for that purpose.

like the others said, always keep your heat down as low as you need to weld. always do short sections, use cold rags to quench heat from time to time, not directly on weld, but adjacent.

good luck

sorry, I noticed the one like in the last message didn't work.

go to


http://www.eastwoodco.com/cgi-bin/s....htm&UID=2002012207355906&FNM=20

and search on "INTERGRIP PANEL CLAMPS " to find them.

they also have many other tools you might find handy.

check out their flanging tools, hole punching tools, also great for patch panel welding.

Good advice, except the part about going to Eastwood for it. I've discovered more and more that Eastwood is WAY overpriced. You can get those clamps (the SAME ones) from Harbor Freight for about a tenth of the cost. Eastwood mostly just resells stuff that is available elsewhere in the market for a lot less.

Good point guys! Save money, buy more parts for the truck!!!!

The clamps for the gap seam, I made some myself, and they work great, I just use tiny machine screws.

I will check harbor freight fo rth pin type clamps, I need some more!

To those of us who live in the Northwest, go to Boeing surplus and get some Clecos. wotk for the airline industry, should work for us too.
Dennis

those of you with one of the new miller 110 welders {150?} do you notice a problem with the cover gas {argon 72/25 mix} not staying on long enough to make a perfect weld? i am a welder by trade and have used and prefered "miller" products all my life, this model seems to cut the cover gas off to soon !the bigger models i dont seem to have a problem with. my weld shop swears only i have complained about this problem.i think most people buying the 110 welders are not experienced enough welding and dont realize there is a problem !right at the end of your weld or tack it seems to fester up and you have to grind it off .

Aircraft Spruce and Specialties (www.aircraftspruce.com) sells a device called a "Cleco". It's harder to explain than it is to show, so I'll not try and confuse you. They have an excellent help line and can get you on the right track. Clecos are used to hold pieces of sheetmetal together while riveting. The washer trick above is very creative.

On a plane, if you need a flush patch out in the middle of a wing (for example), the best repair is called a "Dollar-dime" patch. Your hole in the skin is the size of a dime, and the backer is the size of a silver dollar (not a S.B. Anthony or dollar bill). The "dollar" is riveted to the backside and the "dime" is then flush riveted to the "dollar" as a filler. Clecos hold the whole thing together. You remove the Cleco and install the rivet in the hole. You could subtitute the rivets with stitch welds around the filler and remove the backer if it were brass or copper. Of course any size hole can be repaired this way not just "dime-sized" holes. If you think that was long-winded...ask me how Clecos work.

Stop by your local small airport and ask around for the shop that does sheetmetal repairs on small aircraft. For a cup of coffee, most any sheetmetal guy will show you what I'm talking about along with a bunch of other tricks for sheetmetal repairs. You'll probably find the best TIG/MIG welder in town there too. FAA cert. for welding is no laughing matter.

Good Luck on your project. I hope this helped.